This invention relates to a versatile device for transferring power between rotary and linear reciprocating motion, and offers a wide range of energy efficiency and environmental benefits in engines, compressors, pumps, and other applications. In the prior art, power transfer is generally effected by a crank shaft, for example in internal combustion engines, where the crank shaft converts linear reciprocating motion of pistons to rotary motion of a drive shaft. In compressors, crank shafts are used to convert rotary motion into linear reciprocating motion. Crank shafts are hampered by many factors, including changing crank angulation, the size of crank shaft necessary to accommodate larger stroke lengths, and the increased power required for such larger stroke lengths.
In internal combustion engines with crank shafts, as the power is applied to the piston, it is transmitted toward the center of the crank shaft and no torque is developed. As the crank moves out of line with the piston, the torque transfer begins to increase until it reaches a maximum at the 90 degree point, when the piston is already half way down the cylinder. The crank continues its movement and the torque decreases back to zero at the bottom of the stroke. In compressors and piston pumps using a crank shaft, to increase the volume, the crank or the piston surface must be enlarged, which requires a larger drive motor.
Prior art devices cannot deliver essentially steady power transfer throughout the piston stroke. A number of patents represent attempts to replace the crank shaft with other types of mechanisms. For example, Compton U.S. Pat. No. 1,123,172, issued in December 1914, Short U.S. Pat. No. 1,399,666, issued December 1921, and Noah U.S. Pat. No. 1,636,612, issued July 1927, each involves a shaft that rotates around a fixed axis. Other patents also represent efforts to solve the problems in designing a versatile device capable of efficiently transferring power between reciprocating and linear motion, for example, Webb U.S. Pat. No. 1,687,744 issued October 1928; Koderman U.S. Pat. No. 3,886,805 issued July 1975; Pahis U.S. Pat. No. 4,395,977, issued August 1983; Gaither U.S. Pat. No. 4,443,163, issued April 1984; and White U.S. Pat. No. 4,608,951 issued September 1986. The devices disclosed in these patents are impractical, have too many moving parts, are inefficient, or are overly complex. They do not provide a viable alternative to crank shafts, and are not useful in the wide variety of other applications where it is necessary to transfer power between linear reciprocation and rotary motion.